1. Field of the Invention
The present invention relates to a circuit breaker, and particularly, to an interlock apparatus for a move-out type circuit breaker capable of automatically discharging elastic energy charged in a closing spring and a trip spring upon moved-in or moved-out a main body of the circuit breaker.
2. Background of the Invention
A circuit breaker is a device for automatically detecting an occurrence of fault current on a circuit and breaking the circuit accordingly, thereby protecting lives, circuits and electric load equipment from electrical power accident. The circuit breakers may be classified, according to the size of a rated voltage of electric power used, into a low voltage circuit breaker lower than several hundred volts and a high voltage circuit breaker higher than that.
The present invention relates to an interlock apparatus applicable to a vacuum circuit breaker used as a high voltage circuit breaker among others, and a low voltage air circuit breaker. Compared to a stationary type circuit breaker, the move-out type circuit breaker is a circuit breaker in which a main body of the circuit breaker is separated from a terminal of an outer casing connected to an external power source side circuit and an external electrical load side circuit via terminals, in order to test, repair (maintain) and replace the main body, and then the separated main body is carried to a move-out position, or to a move-in position, at which the main body is connected to the terminal of the outer casing, after completion of the testing, repair and replacement. For the move-out and move-in, transfer wheels are disposed at a lower portion of the main body together with a driving device for the move-out and move-in. The move-out type circuit breaker is globally used in an electric power system due to its stability and convenience upon testing, repairing and replacing the circuit breaker main body as compared to the stationary type circuit breaker.
Further, the move-out type circuit breaker may have a closed position (or so-called on-position) at which a circuit is closed to allow electrical power supply and an open position (or so-called off-position or trip position) at which a circuit is open to break off power supply. The driving (guiding) of the move-out type circuit breaker toward the closed position and the open position is performed by using a force generated when discharging elastic energy, which is charged by tensioning a closing spring and a trip spring, respectively. Upon an occurrence of fault current on a circuit, since it is needed to instantaneously break off the circuit, a substantially great elastic energy of the closing spring and the trip spring is required.
In such move-out type circuit breaker, in order to repair (maintain) or replace the circuit breaker, the main body of the circuit breaker may be moved-out of a connected position with a terminal on the outer casing or moved-in to a connected position with the terminal on the outer casing after the repair or replacement. When pushing in or pulling out the circuit breaker main body, if the closing spring or the trip spring of the circuit breaker is in a state of elastic energy being charged therein, such elastic energy charged in the closing spring or the trip spring may be discharged during operation, causing the chance of incurring risk.